rear tires wear out quick on inside

[johnflight1]

my 88 300 e eats rear tires,I have had 4 wheel alignment at the dealer.I have tried many brands of tires.the wheels suck up into the wheel wells with a big load in the trunk or the back seat 3 people. but 99% of the time its just me and my tools in the trunk. can the springs be shot?lookingat the car from the rear it looks ok. I see many 300e with the wheels way up in the wheel wells and on an angle (tops pointed in) mine don't do this unless its over loaded . is this a common problem with 124 cars? can any one recomend good springs!is alignment required again when the springs are replaced?